It would probably vary from year to year, but at my school, people got in with the following marks:
1) 92 in Physics, 97 in 2U Maths
2) 89 in Physics, 98 in 2U Maths
3) 94 in SDD
and missed out with
88 in SDD and 89 in 2U Maths
The school adds a statement/puts your current other subjects/marks...